Type 304 vs. type 202 stainless steel

A discussion started in
2008 but continuing through 2018

October 7, 2008

Q. I purchase housewares for a US retailer, a foreign manufacturer has told me that 202 grade SS is also approved for the food industry. I have not been able to verify this with the FDA. Other than the low Ni content of 202 SS, how different is it from SS 304? Are there any known implications or reactions in the human body? Any references would also be greatly appreciated.
Thank you

A. The major differences between 202 and 304 stainless steels are in the nickel and chromium contents. 202 has 16-18% chromium and 0.5-4.0% nickel, whilst 304 has 18-20% chromium and 8-10.5% nickel. There are other minor differences in the amount of carbon (0.08% in 304 and 0.12% in 202), manganese (2% in 304 and 5.5-7.5% in 202), as well as slight differences in the silicon, phosphorus and molybdenum contents. Both are austenitic steels and are essentially non-magnetic, but will become temporarily magnetic by working them. The manganese helps preserve the austenitic phase in the steels, as does the nickel. I can see an attraction in some people for using the 202 steel as it contains less nickel, and there is concern amongst some folk that they are sensitive to nickel. However. as far as I am aware, nickel containing stainless steels have not been shown to cause nickel sensitivity - however, I am willing to be shown to be wrong here.

Trevor CrichtonR&D practical scientistChesham, Bucks, UK

December 6, 2008

Q. Can we use magnetic steel for kitchen utensils (is it hygienic and non-rusting)?
And what's the best choice of ss types, and cheapest also to make stainless steel kitchen utensils like basins, mugs, milk pots, etc.
Thank you, and awaiting your kind reply

Dr. Abbas Sholgamiholloware factory - UAE

December 14, 2008

A. You can use magnetic stainless steels if you want to, but the most usual stainless steels are 304 and 316 grades

A. True, but knives are usually some variant of 400 SS which is magnetic. So, what is a utensil?

James Watts- Navarre, Florida

October 2, 2009

Q. CAN WE USE STAINLESS STEEL KITCHEN UTENSILS LIKE DEEP AND FLAT BASINS, TRAYS, BOWLS USING STAINLESS STEEL GRADE SS410? HOW HYGIENIC IS IT AND WHICH IS MORE EASY TO PRESS (WHICH IS SOFTER) SS410 OR SS304?
ALSO HOW TO POLISH MANUALLY SS410 SURFACE BA?

A. Hi Dr. Abbas. 4xx stainless steels are less expensive than type 304 because they contain no nickel. They are less corrosion resistant and more prone to rusting, but they are sometimes used for kitchen utensils. Type 304 work hardens, so it is probably hard to press complicated shapes; I don't really know about type 410, but it probably doesn't work harden.

Is 202 stainless non-magnetic?

January 13, 2014

Q. Hi

I work with NMR instrument which has a ultra shielded superconducting magnet (9.4T) as one part of the instrumentation, other being electronic console. We typically need to climb few wooden steps to reach top of the cylinder which houses the magnet. I want to install railings on both side of these wooden steps to prevent falling from the steps. Is it OK to use SS 202 as material of construction for the railing? I want non-magnetic SS which will not get attracted to the magnet.

Thanks for your help.

Vivek K- India

January 14, 2014

A. Hi Vivek. This sounds to me like an application where true and complete freedom from magnetism is essential. Is there a good reason you can't use aluminum railings?

Regards,

Ted Mooney, P.E.finishing.comPine Beach, New Jersey

August 5, 2014

Q. SS 202 material is Magnetic or Non-Magnetic.

Please confirm.

DINESH NITHIANANDAMcement - Trichy, Tamilnadu, India

July 2014

A. Hi Dinesh. The short answer is that 202 is an austenitic, non-magnetic, stainless steel. But we asked you to post your own situation, not an abstract question because the longer answer starts with "Why do you want to know?" Although it is non-magnetic as annealed, cold working can introduce various degrees of magnetic effects. Due to it's lack of molybdenum, it is more subject to magnetism from cold-working than type 316; I think it's perhaps slightly less subject to such effects than type 304 -- but such answers aren't totally yes or no. A neodymium magnet may attract it too. If your situation is like Vivek's, I'd say 202 is not safely non-magnetic. Good luck.

Regards,

Ted Mooney, P.E.finishing.comPine Beach, New Jersey

February 5, 2014

Q. If SS304 is used instead of SS202 in stair railing in a residential building, is there any extra benefit in terms of look and durability?

Ikbal Ahmed ChoudhuryCivil Engineer - Karimganj, Assam, India

March 27, 2014

A. For an interior handrail, I'd consider 304 and 202 to be pretty identical, because I'm thinking of corrosion resistance in that application (both acceptable) and strength (again, both acceptable). I'm not sufficiently familiar with the formability of 202 to know if it's good, but I'd bet that would be reflected in the price. If the price was right, I'd go with the 202.

Good luck!

Lee Gearhartmetallurgist

August 28, 2014

Q. We need to know which grade of steel can be used in a machine for washing bottles. The inner tanks are SS-304, but outer body can be of MS/SS. As SS-304 makes it 1.5 times costlier, what can be other second best option.

Thanks.

Shilpa Bajpaidairy farming - Gurgaon, Haryana, India

September 20, 2014

Q. Sir
Which grade (202 or 304) is better, economical, lasting to use for window grills?

ABHILASH KP- calicut, Kerala, India

October 29, 2014

A. Hello friends ...

I am working last 5 years in stainless steel fabrication.
Just I want to say that 304 and 316 grade is best of all ... for furniture, railing, etc.

But don't forget about gauge (thickness) -- 16 gauge is better.

pravin joshiclassic steel - Ahmedabad , Gujarat , india

November 29, 2014

A. S/S 304 type is better economically although it's quality is in the middle of 316 and 202, the cost also lies between the prices of 316 and 202.

Basically, S/S 202 is more prone to corrosion when exposed to water and acid solutions. The longevity of S/S 304 is longer than that of 202 although both will corrode over time. But still there are ways to prevent S/S from rusting such as grinding sand paper and buffing.

A. In all of these stainless steels, Cr is trying to form ferrite while the austenitising elements, Ni, N, Mn and Cu, are trying to form austenite. The higher the Cr content, the more austenitising elements are needed to change all the ferrite to austenite. J4 is a good example -- in order to get the Ni level down to 1% Ni, and so minimize the price, it has been necessary to reduce the Cr content to 15-16%. This is much lower than the 18.0 - 20.0% Cr specified for grade 304 and it is Cr which makes the greatest contribution towards corrosion resistance.

This means that such 200-series grades have lower corrosion resistance and are suitable for a much narrower range of applications than grade 304. This has not been well understood and there are many instances where 200-series grades have failed due to corrosion, such as when they have been used for components like handrails in exterior applications.

Ammit Gulati- India. vizag

July 14, 2015

Q. Can you guide whether we should use 304 or 202 for bolts and nuts used for a VCB structure being used in outdoor application.

Md azam Khan- Bhopal , India

July 2015

A. Hi Md Azam. Sorry I don't know what a "VCB structure" is. Google suggests that you might be talking about a "vacuum circuit breaker" or a "visitor & convention bureau" :-(

While we await your clarification, most readers seemed to feel that 304 was a marginally more expensive and corrosion resistant grade.

Q. Can anyone help with the recommendation of steel type and grade for modular steel kitchen? Is there any recommended source from bangalore/india?

chandra, Raj- bangalore, KA, India

----Ed. note: Hi Raj. We hope readers help you with the type and grade! But sorry, the forum is for technical info only; we don't post sourcing info or brand preferences.

June 4, 2015

A. Hi Raj, Modular kitchen are available in MS Steel & Stainless Steel, either 202 or 304 grade. For Bangalore weather conditions 202 grade of SS is more than sufficient; however, there is no debate in the fact that SS 304 is better.

Abhishek KashikarSteel & SS Modular Kitchen dealer - Bangalore, India

January 31, 2015

Q. Why SS 304 grade steel food grade is more costly than others?

Deepa Jayant MiringkarGovt Servant - ponda goa India

February 2015

A. Hi Deepa. The short answer is that type 304 contains 8% nickel which is much more expensive than iron, so it will cost more than nickel-free or low-nickel stainless steels while being more corrosion resistant.

Regards,

Ted Mooney, P.E.finishing.comPine Beach, New Jersey

May 11, 2015

Q. For modular kitchen in indoor use please compare the life of SS 202 & SS 304. Regards,

SP SINGH- delhi, India

A. Hi Singh. My reading of the above responses is that 304 is somewhat more expensive because of its nickel content, and slightly superior in corrosion resistance. But I doubt that anyone will be able to offer quantitative data comparing their life in modular kitchens. But we'll see what if anything is offered in response to your question.

SS 202 or CR Sheet? Which should I use for making my wax candle jars?

February 23, 2015

Q. I have to make a metal jar for wax candles. My prime concern is that it should not rust for a very long time, i.e., 4 to 5 years. Please suggest what are my options--
Can I make it in CR sheet and apply a good quality of melamine or lacquer?
Can I make it in SS 202 Grade and should I apply any melamine or lacquer also?
Please suggest.
Thanks.

Raj RanaRaj Industry - Delhi INDIA

February 2015

A. Hi Raj. Assuming that these are for indoor use, SS 202 sounds fine. CR has no corrosion resistance so you would need proper pretreatment followed by a paint or coating that would not be damaged by the heat.

Regards,

Ted Mooney, P.E.finishing.comPine Beach, New Jersey

September 1, 2015

Q. Sir I have SS pipe, size is 1" x 1" square. Sir it attracts the magnet with full force. Please guide if that one is 202 or what grade it can be of ??
Regards,

Amit guptasteel - Moga, punjab, India

September 2015

A. Hi Amit. If stainless steel is strongly magnetic, it's not austenitic stainless steel (202, 304, 316, 347) unless it has been so strongly cold-worked that it lost much of its austenitic structure. That's all the information that can be gleened from a single binary digit of information like magnetic vs. non-magnetic. Sorry, you need more data; you absolutely cannot tell what grade of stainless steel you have from this one single quality.

Q. Hi all,
I'm new to the SS market; I am planning to go for trading of major types in Himachal Pradesh, planning for railing, pipe and accessories. Anyone guide me which types I can stock more?
Best regards,

rajan vermaProprietor - hamirpur, Himachal Pradesh, India

May 10, 2016

Q. I want to make steel rack and tray for cooling of bread.
Please state me whether I should use steel 202 or 304.

Abdul khalikFood Product - Thane maharastra-INDIA

May 2016

A. Hi Abdul. I'm confident that there are educational/trade organizations in India which serve the baking industry and can warn you about sanitary codes, food & drug manufacturing rules, etc. Lacking such info, type 316SS is the only construction material which I would have confidence in as being fully approved.

I would specifically not go into a cost-cutting program from 304 to 202 in a food industry. Just a personal opinion from someone on a different continent :-)

Readers: a great way to learn is to try to teach. You'll learn far more, far quicker, from attempting to answer an open question here rather than adding yours to the list :-)

Q. Hi, have read the whole thread above and understand that 304 is more resistant to corrosion than 202 and more expensive due to nickel content. I'm specifically looking at products like steel lunch boxes and bottles. Would 202 be sufficient for all practical purposes? Also what about 4xx steel? I'm thinking of 4xx to use the magnetic properties - but any concerns in using it for food? Thanks so much!

Sirisha Gi- Mumbai, India

February 22, 2017

Q. Is ss 202 good for food grade?
There is any chemical reactions when we use it??
Or SS304? Which is best for food grade?
Please suggest?

v rama krishna- Tenali, Andhra Pradesh, India

February 2017

A. Hi cousins. I just finished answering that question to the best of my ability as someone from the metal finishing industry in the USA. Someone from the food service industry in India must chime in with an answer rather than people repeating the questions, if we are to make progress.

Can't thread SS 202 material

Q. Sir, how to do threading operation on SS 202 material? I have tried doing threading by flat die rolling machine but the die gets damaged very often, so please suggest what should I be doing?

Vinit Kavani- Surendranagar, Gujarat, India

February 5, 2018

A. Hi Vinit,

You should check the material of the flat dies of the rolling machine, it's quite different from the ones used for carbon steel. And die material is vital for service life.

I didn't work with SS202, but SS302 and SS304L have nearly the same conformability and they can be threaded by flat die rolling machines provided the right materials for the dies and hardness of the raw material is not too high.

Hope it helps! Regards,

Daniel MontanesTEL - N FERRARIS - Canuelas, Buenos Aires, Argentina

February 26, 2018

Q. Can I use 202 ss square pipe for my windows? My house is at Calicut Kerala. Should I opt 304 while considering quality. I want a long lasting one without any degradation in Kerala climate. My locality is not a coastal region. Kindly give a reply on terms of quality and sustainability.

Thanks
Subi

Subi K BalakrishnanMmm - Calicut, Kerala, India

March 9, 2018

Q. I wish to manufacture SS hotpots or casserole which keeps hot food hot. Can I use SS 202 or 304? I tried to press SS 202 but it is developing cracks on the sides. I was told to use steel with high nickel content. As far as to my knowledge, high nickel content only prevents corrosion and rusting. Why is the hotpot or casserole cracking from the sides?

Parimal kumarappliances - kolkata, India

March 14, 2018

A. Hi Parimal,

Nickel makes stainless more resistant to rust in certain conditions, but more than that, it is the responsible for its austenitic structure. Nickel makes austenite stable and improves speed of self-passivation, and makes all the part non-magnetic.

200-series replaces nickel with manganese, and this element doesn't stabilize austenite as nickel, so you can find other structures after or during cold-forming. You can find more sulfur in the alloy, if it is not informed in some certificate you should ask for it AND measure the raw material, you could be surprised what you can find in these low cost alloys.

Well, keep us posted! Best of luck!

Daniel MontanesTEL - N FERRARIS - Canuelas, Buenos Aires, Argentina

May 17, 2018

Q. This may not be the proper place for my question, but I need to start somewhere. In craft making, what type of stainless steel should I use for a cake tester? Does it need to be food grade since you stick it into food in the oven for a few seconds? Or can I just use a 16 gauge coil of rust proof stainless steel? Thanks.

Cindy Sullivan- Merritt Island, Florida, USA

May 2018

A. Hi Cindy. Although I suppose it is possible to find a stainless steel that isn't 'food grade', most stainless steel is. Your flatware may be type 316SST, your steak knives type 420 or 440A, and pots & pans type 18/0 for example.

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.